1. Field of the Invention
The invention relates to a semiconductor structure and a manufacturing method thereof. More particularly, the invention relates to a package carrier and a manufacturing method thereof.
2. Description of Related Art
The chip package aims at protecting an exposed chip, lower the density of chip contacts, and effectively dissipate heat generated by the chip. A leadframe often serves as a carrier of the chip when a conventional wire bonding technique is applied. As contact density in the chip gradually increases, the leadframe is no longer able to further improve the contact density and thus can be replaced by a package substrate which can achieve favorable contact density. Besides, the chip is packaged onto the package substrate by conductive media, such as metal conductive wires or bumps.
In the most common light emitting diode (LED) package structure, an LED chip need be packaged before the LED chip is used, and the LED chip generates a significant amount of heat when emitting light. Given the heat generated by the LED chip cannot be well dissipated and continues to accumulate in the LED package structure, the temperature of the LED package structure continuously increases. As such, the overly heated LED chip may have luminance decay, shortened life span, or even permanent damages.
As the integrity of integrated circuits continues to increase, the mismatch of the coefficient of thermal expansion between the LED chip and the package substrate often leads to increasing thermal stress and warpage therebetween. Ultimately, the reliability of the connection between the LED chip and the package substrate declines. In addition to enhancement of the light extraction efficiency, the current package technology focuses on decreasing the thermal stress of the package structure to increase the lifetime and the reliability of the package structure.